[Hallicrafters] Any articles on 4-400A Grouded-Grid Amplifier ??

Olaf Madsen Olaf at carolina.rr.com
Sun Feb 19 15:21:57 EST 2006


Hello Fellows,

I aquired a 1960's or 70's homebrew amplifier that uses very,very basic 
grounded-grid circuitry,ala 1972 Handbook.

4-400A tube -- screen and grid directly grounded -- Filaments isolated with 
B&W FC-30 Filament Choke. --No Input circuit,-- direct feed to 
Cathode --National 175  RF Plate Choke--500pF TV doorknobs to by-pass and 
couple to Pi-Network with B&W 851 switched Tankcoil (10-80 mtrs)---3000V on 
the plate--NO PARASITIC SUPRESSION what-so ever.

The amplifier looks very impressive---nice frontpanel,meter and knobs and 
Hallicrafters cabinet ala SX-42,SX-101 and the like.---The transformer 
''weighs a ton''.--Fits right in with the other Hallicrafters Boatanchoers.

Can anyone lead me to an article that might have been used to build this amp 
or cover the subject  (Tetrodes in GG )???---Of course,it wants to ''take 
off'' just turning the Tuning or Output capacitors.

Tnx in advance es 73's---Olaf,---KF4TP---  




More information about the Hallicrafters mailing list